Hello, the reason why the bank wants to extend the loan period is because your family's monthly income is not enough to repay the monthly payment, so the bank will ask to increase the down payment ratio or extend the loan period to solve this problem. Personally, if the money on hand is not too surplus, it is better to increase the loan period. If the time value, opportunity cost and the current low loan interest rate are counted together, it will be better for customers if their life span is increased for several years.

I hope my answer can help you.